<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <button v-on:click="add">+</button>
        <span>{{num}}</span>
        <button v-on:click="sub">-</button>
    </div>
</body>
<script src="./node_modules/vue/dist/vue.js"></script>
<script>
    let vm = new Vue({
        el:"#app",
        data:{
            num:111,
        },
        // 定义实例上的方法
        methods:{
            add:function(){
                this.num++;
            },
            sub:function(){
                this.num--;
            }
        }

    });
</script>
</html>